Follicular Dendritic Cell Sarcoma : Microscopic
Follicular Dendritic Cell Sarcoma (FDCS): The tumor is composed of spindle, oval, or epithelioid cells arranged in fascicular, storiform, whorled, or diffuse growth patterns. Some cases have an appearance reminiscent of meningiomas. Others show dense fibroblastic areas. The nuclei are oval with vesicular appearance, finely granular chromatin, and punctate nucleoli. The cells have moderate amount of fibrillar eosinophilic cytoplasm with indistinct borders, imparting a syncytial appearance.
The background consists of small lymphocytes, or sometimes plasma cells, in close association with the cellular processes of spindle cells. Cystic areas or foci with myxoid change may be present. Necrosis is uncommon and is an adverse prognostic sign.
Grading: Most FDCS are considered low-grade sarcomas. However, some deep-seated lesions may show foci with significant nuclear pleomorphism, abnormal mitoses, and necrosis.